The reclamation of metals from discarded automobiles and other end-of-life equipment has become a highly mechanized operation requiring a maximum degree of optimization in terms of the conservation of materials and energy. The importance of recycling such scrap materials as iron, copper, aluminum and other metals becomes increasingly apparent as the depletion of ore reserves drives prices higher and higher. At the same time, the high cost of fuels and the high level of energy utilization involved in the separation and refinement of metals makes it doubly important that the salvage operations be rendered as effective and efficient as possible.
In a typical salvage operation, complete automobile bodies including frames, engines, seats, upholstery and the rest are first crushed and compacted for shipment to a salvage operation. The compacted automobiles are then fed into a shredder, a huge and powerful machine with heavy cleated roller size pieces of iron, steel, brass, glass, etc. As these pieces of scrap metal are exhausted from the shredder, a large percentage of the ferrous materials are separated from the mass of the material by means of a large magnetic roller, but the residue contains along with the glass, cloth, rubber, wood, dirt, tar, etc., a significant amount of ferrous and non-ferrous metals which must be salvaged for reuse.
Heretofore the separation of metals from this residue was largely a hand operation in which the useful materials were picked from a moving conveyor belt. Because of the high cost of labor there is a limit to the percentage of the total metal content of the residue which can be recovered in this manner, i.e., bits and pieces of metal below a given size are not worth the cost of the labor required for separation.
While various known chemical, electro-chemical and metallurgical processes are useable for the recovery of the balance of the materials that are not removed by hand separation, the costs of these processes including the high energy costs involved suggest the need for a mechanized alternative to the hand-picking operation.